The present invention relates generally to plastic bags. More particularly, the present invention relates to the use of materials in plastic bags to strengthen the fins and/or profiles of fasteners in plastic bags.
Plastic bags are in widespread use in a varied and diverse number of household and commercial applications, especially in the food packaging industry. One advantage of plastic bags is their ease of opening and resealing. Some of these bags are reclosable via the use of a reclosable feature such as a reclosable fastener. In many bags, the fasteners can be opened and closed either by pressure or by the use of an auxiliary slider mechanism.
A factor which affects the acceptance and range of application of plastic bags is the strength and reliability of the reclosable fasteners on the bags. Many of the presently available reclosable fasteners are made of materials such as low density polyethylenes and linear low density polyethylenes which do not have sufficient mechanical strength to prevent the fasteners from opening. The failure of the fasteners may result in spillage of the contents of the bags and can lead to extreme customer dissatisfaction.
Since the popularity of plastic bags has placed increased demands on the tasks they are asked to perform, a need exists for bags having fasteners that are able to withstand increased forces and more adverse conditions.
According to one embodiment, a fastener for a plastic bag comprises a male track including a male profile and a first fin extending from the male profile and a female track including a female profile and a second fin extending from the female profile. At least one of the first and second fins comprises a cyclic olefin copolymer. The cyclic olefin copolymer has a glass transition temperature, Tg, of greater than about 20xc2x0 C. as determined by ASTM D3418. The cyclic olefin copolymer may comprise from about 10 to about 90 mol. % norbornene. At least one of the first and second fins may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof.
According to another embodiment, a fastener for a plastic bag comprises a male track including a male profile and a first fin extending from the male profile and a female track including a female profile and a second fin extending from the female profile. At least one of the male and female profiles comprises a cyclic olefin copolymer. The cyclic olefin copolymer has a glass transition temperature, Tg, of greater than about 20xc2x0 C. as determined by ASTM D3418. The cyclic olefin copolymer may comprise from about 10 to about 90 mol. % norbornene. At least one of the male and female profiles may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof.
According to another embodiment, a fastener for a plastic bag comprises a male track including a male profile and a first fin extending from the male profile and a female track including a female profile and a second fin extending from the female profile. At least one of the male and female profiles comprises a cyclic olefin copolymer and at least one of the first and second fins comprises a cyclic olefin copolymer. The cyclic olefin copolymer has a glass transition temperature, Tg, of greater than about 20xc2x0 C. as determined by ASTM D3418. At least one of the first and second fins may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof At least one of the male and female profiles may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof.
According to a further embodiment, a polymeric bag comprises first and second opposing body panels fixedly connected to each other along a pair of sides and a bottom bridging the pair of sides and a reclosable fastener extending along a mouth formed opposite the bottom. The fastener includes a pair of interlocking flexible plastic tracks including a male track including a male profile and a first fin, the first fin extending from the male profile and a female track including a female profile and a second fin, the second fin extending from the female profile. At least one of the first and second fins comprises a cyclic olefin copolymer. The cyclic olefin copolymer has a glass transition temperature, Tg, of greater than about 20xc2x0 C. as determined by ASTM D3418. The cyclic olefin copolymer may comprise from about 10 to about 90 mol. % norbornene. At least one of the first and second fins may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof. The bag may comprise a slider slidably mounted to the fastener for movement between a closed position and an open position.
According to a still further embodiment, a polymeric bag comprises first and second opposing body panels fixedly connected to each other along a pair of sides and a bottom bridging the pair of sides and a reclosable fastener extending along a mouth formed opposite the bottom. The fastener includes a pair of interlocking flexible plastic tracks including a male track including a male profile and a first fin, the first fin extending from the male profile and a female track including a female profile and a second fin, the second fin extending from the female profile. At least one of the male and female profiles comprises a cyclic olefin copolymer. The cyclic olefin copolymer has a glass transition temperature, Tg, of greater than about 20xc2x0 C. as determined by ASTM D3418. The cyclic olefin copolymer may comprise from about 10 to about 90 mol. % norbornene. At least one of the male and female profiles may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof. The bag may comprise a slider slidably mounted to the fastener for movement between a closed position and an open position.
According to a still further embodiment, a polymeric bag comprises first and second opposing body panels fixedly connected to each other along a pair of sides and a bottom bridging the pair of sides and a reclosable fastener extending along a mouth formed opposite the bottom. The fastener includes a pair of interlocking flexible plastic tracks including a male track including a male profile and a female track including a female profile. At least one of the male and female profiles comprises a cyclic olefin copolymer. The cyclic olefin copolymer has a glass transition temperature, Tg, of greater than about 20xc2x0 C. as determined by ASTM D3418. The cyclic olefin copolymer may comprise from about 10 to about 90 mol. % norbornene. At least one of the male and female profiles may comprise an additional polymer selected from a polyolefinic resin, an engineering resin, and a combination thereof The bag may comprise a slider slidably mounted to the fastener for movement between a closed position and an open position.
The above summary of the present invention is not intended to represent each embodiment, or every aspect, of the present invention. This is the purpose of the figures and the detailed description which follow.